1. Field of the Invention
The present invention relates to a hinge used in an office-automation apparatus, and more particularly to a tilting hinge suitably usable to support, at a desired opened or closed angular position, a display screen of a portable computer such as a notebook or laptop computer.
2. Description of the Prior Art
A tilting hinge intended for use with a display screen of a portable computer as an office-automation apparatus and which uses only a friction mechanism to stably support the display screen at an intermediate opened angular position is already known from the disclosure in, for example, the Japanese Published Unexamined Patent Application No. Heisei 9 (1997)-62399. This conventional tilting hinge includes a fixture consisting of a fixing plate portion which is to be fixed to the body of a portable computer and a bearing plate portion bent perpendicularly to the fixing plate portion; a rotating shaft having a fixing portion born rotatably in a bearing hole formed in the bearing plate portion of the fixture and which is to be fixed to a display screen of the portable computer; a first friction washer having a through-hole formed in the center thereof and disposed between a large-diameter portion of the rotating shaft and one side of the bearing plate portion rotatably with the rotating shaft being inserted in the central through-hole or disposed in engagement with the bearing plate portion; a second friction washer having a non-circular through-hole formed in the center thereof and disposed to abut on the other side of the bearing plate portion rotatably with the rotating shaft being inserted at a non-round small-diameter portion thereof in the central non-circular through-hole; an elastic assembly of a spring washer or spring washers, a belleville spring or belleville springs, a wave washer or wave washers, etc. each having a through-hole formed in the center thereof, the assembly being disposed to abut on the second friction washer with the rotating shaft being inserted at the non-round small-diameter portion thereon in the central through-hole; and a set washer having a non-circular through-hole formed in the center thereof and disposed to abut on the elastic assembly rotatably with the rotating shaft being inserted at the non-round small-diameter portion thereof in the central through-hole; a projection, from the set washer, of the non-round small-diameter portion of the rotating shaft being calked so that a friction torque will develop between the first friction washer and the large-diameter portion of the rotating shaft or the bearing plate portion as well as between the second friction washer and the bearing plate portion or spring washer.
The above conventional tilting hinge is advantageous in that it has a simple structure and can support the display screen stably and securely at the intermediate opened angular position, and so it is adopted in many portable computers. With the conventional tilting hinge, however, the operating force required for stably supporting the display screen at the intermediate opened angular position is also required for supporting the display screen at other opened angular positions.
Also, since the friction torque is constant with the display screen supported at any angular positions of the display screen, a reactive force will remain in the conventional tilting hinge when the display screen is closed. To minimize the reactive force, the conventional tilting hinge has to include a locking mechanism provided between the display screen and the computer body.
Accordingly, the present invention has an object to overcome the above-mentioned drawbacks of the prior art by providing a tilting hinge adapted to allow to open or close, with a small operating force, a display screen at any angular positions other than an angular position at which the display screen can be stably supported, and eliminate the reactive force without any locking mechanism.
The above object can be attained by providing a tilting hinge, including according to the present invention, a fixture consisting of a fixing plate portion to be fixed to the body of a portable computer and a bearing plate portion bent perpendicularly to the fixing plate portion; a rotating shaft consisting of a fixing portion to be fixed to a display screen of the portable computer, a large-diameter portion and a small-diameter portion, and born relatively rotatably in a bearing hole formed in the bearing plate portion of the fixture; a first friction washer having a through-hole formed in the center thereof and disposed between the large-diameter portion of the rotating shaft and one side of the bearing plate portion rotatably with the rotating shaft being inserted in the central through-hole or disposed in engagement with the bearing plate portion; a second friction washer having a through-hole formed in the center thereof and disposed fixed to the bearing plate portion with the rotating shaft being inserted at the small-diameter portion thereof in the central through-hole or rotatably with the rotating shaft; an elastic assembly of a spring washer or spring washers, a belleville spring or belleville springs, a wave washer or wave washers, etc. each having a through-hole formed in the center thereof, the assembly being disposed to abut on the second friction washer with the rotating shaft being inserted at the small-diameter portion thereon in the central through-hole; a set washer having a through-hole formed in the center thereof and disposed to abut on the elastic assembly rotatably with the rotating shaft being inserted at the small-diameter portion thereof in the central through-hole; the rotating shaft having a to-be-calked projection, from the set washer, of the small-diameter portion thereof; and a torque controlling means for generating, axially of the rotating shaft at either of the sides of the bearing plate portion, a torque varying depending upon the angle of rotation of the rotating shaft.
In the above tilting hinge according to the present invention, the torque controlling means may be formed from a concavity or convexity formed on the second friction washer and a torque plate having formed thereon a convexity or concavity opposite to the concavity or convexity on the second friction washer, or it may be formed from a concavity or convexity formed on the first friction washer and a torque plate having formed thereon a convexity or concavity opposite to the concavity or convexity on the second friction washer.
Also in the above tilting hinge, when the torque plate is used, a spacer may be provided between the torque plate and bearing plate portion.
Also in the above tilting hinge, the torque controlling means may be formed from a convexity or concavity formed on the bearing plate portion and the first or second friction washer on which there are formed a convexity or concavity opposite to the concavity or convexity on the bearing plate portion.
Also in the above tilting hinge, when the concavity to abut on the convexity on the first or second friction washer is formed on the bearing plate portion, a space may be provided in which a convexity projecting to the opposite side to the concavity is received.
Also in the above tilting hinge, a set nut may be provided in place of the to-be-calked projection of the small-diameter portion of the rotating shaft and a lubricant may be applied between the first and second friction washers and members which are rotated in friction with the friction washers when the rotating shaft is rotated.
These objects and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.